Is your treadmill test positive? I know, you might be a little worried about it. But it doesn’t always have to be concerning.
Let’s take a look at what a positive treadmill test means, and what steps you need to take after that.
The Treadmill Test
I will not go into too much detail about treadmill tests here. I have already covered it in detail in a post here.
In short, a treadmill test is done to evaluate how strong your heart is. It also provides information on whether there is sufficient quantity of blood reaching the heart through the arteries when you exercise.
A treadmill test is considered negative if sufficient exercise is done and there are no symptoms or no changes in your ECG.
On the other hand, a positive treadmill test is diagnosed when you have chest pain on the treadmill, or you have ECG changes, or both.
Treadmill Test Positive – Should I Be Worried?
If a treadmill test is positive, it could indicate an underlying heart problem. Some people call this heart trouble ‘blockages’.
The purpose of the treadmill test is to know whether there are any ‘blockages’ in the heart arteries.
In other words, ‘is there coronary artery disease that is the reason for my symptoms?’
Well, it may not always be the case.
A treadmill test is only about 60% sensitive. This means that around 6 out of 10 patients who have a positive treadmill test actually have heart disease.
In other words, 4 out of 10 don’t have heart disease despite their treadmill test being positive.
This is called a ‘false positive’ result. It tends to be very common in women.
A false positive result is one where the treadmill test is positive, but subsequent angiography is completely normal. This means that despite you having a treadmill test positive, you have no blockages in your arteries.
Obviously, having a treadmill test positive can be quite disconcerting. But it is nothing to worry about.
I usually tell my patients that it is a good thing that the test has found that there is something wrong with their heart. This way, if any further treatments need to be given, it will not be when it is too late.
So, now you have a positive treadmill test, what’s next?
Its All About Risk…
Before deciding on further evaluation and tests, I generally look at the patient’s cardiac risk
If a patient has undergone a routine treadmill test and does not have any risk factors (smoking, diabetes, high blood pressure, family history of heart disease, high cholesterol), then the best test moving forward would be a CT coronary angiogram.
A CT coronary angiogram is reserved for those patients who fall in the low to moderate risk category. It picks up any narrowings or blockages with a good deal of sensitivity and specificity.
However, if a patient is very elderly, then a CT angiogram may not be the ideal test. In fact, whether or not angiography should be done at all is a matter of debate.
This is because there is likely to be some disease, and the vessels would have become rather thickened and calcified.
Furthermore, the patient may not be a very active one, and may be rather frail.
A CT angiogram is not very accurate if there is too much calcium in the vessels.
So what’s the next scenario?
If a CT angiogram in a low to moderate risk patient shows significant disease of more than 70% in the major vessels of the heart, then a diagnostic coronary angiogram (done in a hospital) will likely be recommended.
This will help inform us with near 100% certainty about how bad the heart arteries are.
Based on the findings of this angiogram, final treatments (medical management alone vs. stenting vs. bypass surgery) will be advised.
Also, in a patient with multiple risk factors who has a positive treadmill test, there is no point doing a CT angiogram.
It is better in such a situation to do a hospital based diagnostic coronary angiogram.
This way, a definitive diagnosis can be made earlier and treatment started sooner.
Does A Negative Treadmill Rule Out Heart Disease?
There have been many occasions where patients give a textbook description of cardiac pain but have a negative treadmill.
I have then gone on to perform coronary angiography and found them to have some coronary disease.
These tests are false negative results. In other words, there is coronary disease but the treadmill test is negative. Studies have found around 20% of cases to demonstrate this.
In fact, there are even case reports where patients have done really well on a treadmill test and have then gone on to have a heart attack within a few months.
The decision on further tests is experience-based many times. There are no clear guidelines as such that dictate what tests need to be done and when.
I personally feel that treadmill testing is become a little obsolete. While it is useful to evaluate exercise tolerance in patients, the high false positive and false negative rates make it unreliable. It would be better to undergo a CT scan or a stress thallium study to evaluate coronary circulation. However, the limiting factor in India is the cost.
A treadmill test cost in India is around Rs 1000 – Rs 2000. On the other hand, a CT coronary angiogram costs around Rs 10000 while a stress thallium test costs around Rs 15000. A diagnostic coronary angiogram costs between Rs 15000 to Rs 25000, depending on the center. Government hospitals with the set up will be undoubtedly cheaper.
If you have a treadmill test positive, it is not really something to panic about. However, it is strongly recommended that further tests be done, as it is never written in stone that the test is false positive or false negative till the tests are done.
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